The brain’s reaction to stress may be an important contributor to chest pain in patients with coronary artery disease (CAD), according to results of a cohort study.
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“Although more research is needed, these results may potentially shift the paradigm by which angina is evaluated by refocusing clinical evaluation and management of psychological stress as adjunct to traditional cardiac evaluations,” wrote Kasra Moazzami, MD, MPH, of Emory University in Atlanta, and his coauthors in Circulation: Cardiovascular Imaging.
To determine if an association exists between stress-induced frontal lobe activity and angina, the researchers launched a study of 148 patients with stable CAD. Their mean age was 62, 69% were male, and roughly 36% were Black. Angina symptoms were assessed at baseline and also after 2 years through the Seattle Angina Questionnaire’s angina frequency subscale.
As the patients underwent stress testing that included both speech and arithmetic stressors, they also received eight brain scans via high-resolution positron emission tomography (HR-PET) brain imaging. Two scans occurred during each of the two control and two stress conditions. Subsequent analysis of these images evaluated regional blood flow relative to total brain flow. Each patient also underwent myocardial perfusion imaging (MPI) at rest, under stress conditions, and during conventional stress testing.
At baseline, patients who reported experiencing angina monthly (35) or daily/weekly (19) had higher rates of mental stress–induced ischemia, more common symptoms of depression and anxiety, and more use of antidepressants and nitrates. Patients reporting angina during stress testing with MPI had higher inferior frontal lobe activation (1.43), compared with patients without active chest pain (1.19; P = 0.03). Patients reporting angina during stress testing also had fewer years of education, higher Beck Depression Inventory scores, and higher posttraumatic stress disorder (PTSD) checklist scores.
More angina correlates with more mental stress
At 2-year-follow-up, 28 (24%) of the 112 returning patients reported an increase in angina episodes. Those patients had a higher mean inferior frontal lobe activation with mental stress at baseline, compared with returning patients who reported a decrease in chest pain frequency (1.82 versus 0.92; P = .01).
After adjustment for sociodemographic and lifestyle variables, any doubling in inferior frontal lobe activation led to an increase in angina frequency by 13.7 units at baseline (95% confidence interval, 6.3-21.7; P = .008) and 11.6 units during follow-up (95% CI, 4.1-19.2; P = .01). After relative importance analysis, the most important correlate of angina was found to be inferior frontal lobe activation at 36.5%, followed by Beck Depression Inventory score and PTSD checklist score.
‘It shows that the heart and brain are connected’
“Previous studies have linked mental stress with ischemia using nuclear stress testing. This study is unique in that it looked at brain activity associated with mental stress and was able to correlate that activity with angina,” said cardiologist Nieca Goldberg, MD, of NYU Langone in New York City in an interview. “It shows that the heart and brain are connected.”
The authors acknowledged their study’s limitations, including using standard stress-inducing protocols that did not account for or reflect any real-life stressors. In addition, although their methods are still considered clinically relevant, retrospectively collecting angina symptoms via questionnaire rather than a prospective diary could have led to incomplete responses.
Dr. Goldberg noted that additional research should include a more diverse population – women in particular were underrepresented in this study – while focusing on how interventions for stress can play a role in angina symptoms and brain activity.
That said, she added, “until there are more studies, it is important to consider mental stress in assessing angina symptoms in patients.”
The study was supported by grants from the National Institutes of Health. The authors reported no potential conflicts of interest.
SOURCE: Moazzami K et al. Circ Cardiovasc Imaging. 2020 Aug 10. doi: 10.1161/circimaging.120.010710.